1. Field of Invention
This invention relates to opposed reciprocating piston mechanisms such as internal combustion engines. The combustion chamber has a unique inlet air valve and volume adjuster. An integrated self-supercharger and regenerator are new and not previously seen.
2. Description of prior Art
An internal combustion engine is a machine that converts chemical energy to mechanical energy. The engine controls and surrounds the chemical reaction. The chemical reaction produces heat and combustion gases which are converted to mechanical power. The present art has improved this conversion efficiency however more energy is exhausted as hot gases than converted to mechanical power. Better conversion of these hot gases to power has been the target of many inventors.
A major improvement has been the addition of a turbocharger. Turbochargers use energy in the exhaust stream that would otherwise be wasted. The turbine in the exhaust stream effectively converts the exhaust manifold into a post-combustion chamber that salvages some the exhaust energy. The other half of a turbocharger is a compressor in the inlet manifold which adds a pre-combustion chamber to increase the air pressure and density of the air charge. A turbocharger increases efficiency because it salvages energy that would otherwise be lost and it increases power density because the same size engine can combust a greater mass of air/fuel.
As good as turbochargers are, they have some weaknesses: 1) They do not work at low power levels because the velocity of the exhaust gases is insufficient to drive the turbine; 2) At high power, they extract more power than needed to compress the inlet air charge; and 3) At high power the added boost increases the effective compression ratio and results in even higher energy content which is lost in the exhaust stream. It is the goal of my invention to correct these deficiencies.
U.S. Pat. No. 4,437,437 has a secondary expansion chamber to extend the power stroke. Erickson eliminates the simultaneous opening of the intake and exhaust valves. Erickson employed a suction chamber to aid in purging the combustion chamber. This improvement reduces the exhaust pressure to be below atmospheric to improve volumetric efficiency. In my design, the combustion chamber and regenerator are always at or above atmospheric pressure.
U.S. Pat. No. 5,341,774 is closer to a Wankel engine than a reciprocating engine with pistons. Erickson demonstrated improved fuel efficiency by extending the power stroke to another chamber. This is an extension of an earlier patent and is now supercharged in this patent. This engine has better fuel efficiency than a traditional two-stroke. It does not have a regenerative phase.
U.S. Pat. No. 4,767,287 has reciprocating piston movement and there are no connecting rods. However there is no supercharging, no multi-chambers and the cycle is not thermodynamically close to this invention.
U.S. Pat. No. 6,314,923 has opposed cylinders, used in a two-stroke engine without connecting rods. This invention uses poppet valves to eliminate simultaneous port openings and the resultant fuel loss. Each cylinder supercharges its mate. The supercharger is not self regulated as in the present invention and supercharges the opposed cylinder. This necessitates lengthy gas passageways. There is no regeneration chamber.
U.S. Pat. No. 7,121,235 has many features contained in U.S. Pat. No. 6,314,923. Similarities are: double pistons used in pairs, reciprocating piston without connecting rods, self supercharging and secondary expansion. However Schmied increases the compression ratio whereas the proposed invention maintains a constant compression ratio. Schmied's claim 6 is similar to U.S. Pat. No. 5,341,774. Schmied's invention has secondary expansion chambers. He uses ducting and secondary valves to transport the gases to the chambers. Schmied operates the exhaust valves with a belt arrangement, see his FIG. 66. My invention operates the exhaust valves directly from the crankpin. Schmied combines exhaust gases from a common port for each cylinder pair. Then he directs the combustion gases to the other cylinder to assist in supercharging. This is effectively a positive displacement supercharger assist. In my engine, the combustion gases move directly to an encircling regeneration chamber. My invention also inducts fresh cold air into the regenerator for each cycle. The combustion gases then heat the trapped cold air for farther expansion.
The value of two-stroke engines is explained and improved by Springer, U.S. Pat. No. 5,526,778 who discloses an adjacent supercharger to improve the air flow through a combustion chamber. Two-stroke engines are farther improved by Hofbauer in U.S. Pat. No. 6,170,443 where he uses two opposed cylinders to provide smooth power with supercharged axial scavenging. He also solves a dynamic problem by balancing the opposed piston weight. Marks, U.S. Pat. No. 4,767,287, discloses a clever way to reduce friction in opposed two-strokes engines by utilizing an oscillating cylinder.